from math import gcd

from math import factorial as f

from math import ceil, floor, sqrt
import math

import bisect
import re
import heapq

from copy import deepcopy
import itertools
from itertools import permutations

from sys import exit

ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(map(int, input().split()))

yes = "Yes"
no = "No"


def main():
    x = ii()
    if x >= 30:
        print(yes)
    else:
        print(no)


main() from math import gcd from math import factorial as f from math import ceil, floor, sqrt import math math import bisect bisect import re re import heapq heapq from copy import deepcopy import itertools itertools from itertools import permutations from sys import exit ii = lambda: int(input()) ii lambda: int(input()) int(input()) int input() input mi = lambda: map(int, input().split()) mi lambda: map(int, input().split()) map(int, input().split()) map int input().split() ().split () input split li = lambda: list(map(int, input().split())) li lambda: list(map(int, input().split())) list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split yes = "Yes" yes "Yes" no = "No" no "No" def main():
    x = ii()
    if x >= 30:
        print(yes)
    else:
        print(no) main x = ii() x ii() ii if x >= 30:
        print(yes)
    else:
        print(no) x >= 30 x 30 print(yes) print yes print(no) print no main() main mi = lambda: map(int, input().split()) lambda: map(int, input().split()) mi yes = "Yes" "Yes" yes no = "No" "No" no li = lambda: list(map(int, input().split())) lambda: list(map(int, input().split())) li ii = lambda: int(input()) lambda: int(input()) ii def main():
    x = ii()
    if x >= 30:
        print(yes)
    else:
        print(no) def main():
    x = ii()
    if x >= 30:
        print(yes)
    else:
        print(no) main
from math import gcd

from math import factorial as f

from math import ceil, floor, sqrt
import math

import bisect
import re
import heapq

from copy import deepcopy
import itertools
from itertools import permutations

from sys import exit

ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(map(int, input().split()))

yes = "Yes"
no = "No"


def main():
    x = ii()
    if x >= 30:
        print(yes)
    else:
        print(no)


main()
